Senator John McCain has criticized Donald Trump a few different times over the past month, as Trump’s behavior has become increasingly inappropriate and unpatriotic. However, after Trump publicly sided with Russian President Vladimir Putin on Saturday and attacked the U.S. intelligence community in the process, McCain lit into Trump in his most scathing condemnation to date.

McCain posted this statement on his official Senate web page: “President Trump today stated that he believed Vladimir Putin is being sincere when he denies Russian interference in the 2016 presidential election and reiterated that he hopes to cooperate with Russia in Syria. There’s nothing ‘America First’ about taking the word of a KGB colonel over that of the American intelligence community. There’s no ‘principled realism’ in cooperating with Russia to prop up the murderous Assad regime, which remains the greatest obstacle to a political solution that would bring an end to the bloodshed in Syria. Vladimir Putin does not have America’s interests at heart. To believe otherwise is not only naive but also places our national security at risk.”

The question now is where this goes from here. A handful of prominent Republican Senators including Bob Corker and Jeff Flake have also condemned Donald Trump of late, though none of them have said anything as of Saturday night in response to Trump’s deranged remarks about Putin. It’s clear that Trump is not mentally competent to do the job, and it’s equally clear that his personal allegiance is to a foreign enemy of the United States. He must be immediately removed from office, but impeachment would require the cooperation of the Republican majority in Congress.

After John McCain issued his statement, Donald Trump went on a psychotic rant on Twitter in which he called Americans “haters and fools” for daring to question why he’s aligned with Putin, and then he twice asked Putin for help. This situation is no longer tenable, and the GOP has an obligation to remove Trump from power immediately.